OK, so a bit of a contrived wording but I was wondering yesterday as I was at DFW looking at all the departures heading across the country whether the shortest routes between any cities in the 50 states with commercial air service required more than three flights.

i.e. you fly from Podunkville on the west coast to a hub, then to another hub on the east coast and then another hop to Smalltown on the east coast. Three flights...but are there any where you'd need a fourth?

I tried thinking of examples where four flights might be needed starting with Hawaii to the East Coast but couldn't think of any. The same with Alaska where the ANC-Lower 48 options gave connections to all places on the east coast I could think of...

Anywhere there is a tag on, and possibly somewhere where you have limited or no legacy service.

Lets say a UA flight goes DEN to somewhere in Idaho to somewhere in Montana. Technically you have two flights there just to get to your final destination. SO like RDU - IAD - DEN - Idaho - Montana.

Or maybe somewhere in texas that is only served by WN (or a single carrier). Somewhere alabama to ATL to whereever on Airtran, then connect to a smaller airline to get to final destination. This would work if the airport at either end is only served by 1 carrier.

Some of your Alaska cities to the southeast might be, especially a city that only has US service to CLT. It also depends on how you define a "flight" - as a "takeoff and landing" or as a "flight number". Some flights do a "Milk Run" from the hub, running HUB-ABC-DEF-HUB. Time of year would play a factor too, since I don't believe ANC is year-round from a city like ATL, so to get from say Valdosta, Georgia to Dutch Harbor, Alaska would take 4 flights at certain times of the year.

Petersburg, AK - Juneau, AK - Seattle, WA - (many choices here) - Ft. Myers, FL - Marathon, FL would require a minimum of five segments to get between those two city pairs.

RSW-Marathon is only served by Continental Connection/Cape Air and is the only route out of Marathon. Petersburg, AK only sees service on Alaska to Juneau/Wrangell.

Those are two legs, and there are no nonstops between SEA and RSW. Plenty of options to get you between the two - AirTran via ATL, American via DFW/ORD, Continental via EWR/CLE/IAH, Delta via MSP/ATL/DTW/CVG, JetBlue via JFK, Southwest via MDW/STL, United via ORD, USAir via PHL/CLT and I could go on.

Johnstown, Pennsylvania only has service to Washington - Dulles Int'l on United Express. So to get to some airports in Hawaii that only have service to Honolulu, such as Hilo, would require four flights, since there is no IAD-HNL nonstop.